1. Field of the Invention
This invention relates to metal-ceramic composite bodies, and more particularly to a metal-ceramic composite body produced by positioning a fitting between metal and ceramic.
2. Related Art Statement
In general, ceramic members are durable at elevated temperatures and have high strength and hardness and excellent corrosion resistance, so that attempts have been made to use them for various applications requiring high strength and wear resistance under high temperature environment, such as engine parts for automobiles, gas turbine parts and parts for industrial machines, and among them some parts have been practised. In these parts, however, the use of the ceramic member alone is a rare case, and a combination of the ceramic member with a metallic member is usually used for the following reason. That is, although the ceramic members have the aforementioned excellent properties, they are difficult to work and they are brittle, so that the ceramic member is applied to only a required portion of the part and the remaining portion of the part is constructed with the metallic member easy to work.
Currently, there are many methods of joining the ceramic member to the metallic member, among them fitting ceramic and metal such as press fitting, shrink fitting, cold fitting or the like.
In general, when the fitting between the ceramic member and the metallic member is, for example, a shrink fitting, if the ceramic member is a column and the metallic member is a cylinder or is provided at the end portion with a receiving hole, the interference S is represented by the following equation: EQU S=D.sub.C -D.sub.M,
wherein D.sub.C is a diameter of the columnar ceramic member and D.sub.M is an inner diameter of the cylindrical metallic member. In this case, since D.sub.C &gt;D.sub.M, when a clearance in the shrink fitting operation is C, the given interference is obtained by heating the metallic member up to a temperature satisfying D.sub.M .gtoreq.D.sub.C +C, inserting the ceramic member into the expanded metallic member and then cooling the metallic member to room temperature.
However, since the face pressure (or fitting force) is proportional to the interference S, it is required to severely control the sizes of the ceramic member and the metallic member for controlling the face pressure. That is, it is required to work the diameters of these members with a considerably high accuracy for controlling the face pressure. However, the working of the ceramic member is particularly difficult, requiring great labor.